Apparatus for reproducing sound from film records



Feb. 17, 1931. c. L. HEISLER 1,793,399

AP ARATUS FOR REPRODUCING SOUND FROM FILM RECORDS Filed March 29, 1929 F'L l. 7 i

nmnummnmum Inventor- Char-Les HeLsLer', 5 MM HLs AttSr-ne Patented Feb. 17, 1931 UNITED" STATES PATENT OFFICE CHARLES I4. EEISLEB, OF SCHENECTADY, NEW YORK, ASSIGNOIR TO GENERAL ELEC- TRIO COMPANY, A CORPORATION OF NEW YORK APPARATUS FOR REPBODUCING SOUND FROM FILM RECOlBDS Application filed March 29, 1929. Serial No. 351,066.

My invention relates to apparatus for reproducing sound from film sound records and particularly to the apparatus by which the record film is supported and moved at the point at which the record is read ofi the film.

The object of myinvention is the provision of improved apparatus of this character having advantages as to simplicity in construction and to convenience and (efficiency of operation which will appear as the description proceeds.

My invention will be better understood from the following description taken in connection with the accompanying drawing, and

its scope will be pointed out in the appended claims.

Referring to the drawing, Fig. 1 is a side elevation partly in section of a preferred embodiment of my invention; Fig. 2 is a view at right angles to that of Fig. 1 also partly in section; Fig. 3 is a cross sectional viewof the photo-electric cell, and its enclosing housing drawn to a greatly enlarged scale; Fig. 4

shows the photo-electric cell housing and socket member therefor separated from each other; and Fig. 5 is a side view of the photoelectric cell and its housing drawn to an enlarged scale.

In illustrating my invention I have chosen :0 for the sake of greater simplicity to show it as a sound reproducer only, it being noted that the film is shown having a sound record thereon but no picture'record. My invention is equally applicable, however, to a machine for pro ect-ing pictures and reproducing sounds from a film bearing both picture and sound records.

In the simplified form of my invention the enclosing casing 1 supports the reel housing 2 containing the take-oft reel 3 and the takeup reel 4 whose construction is like that commonly employed in motion picture machines.

The film 5 is shown as being of the motion picture type-having two marginal. rows of 45 sprocket tooth openings and as havmg a s ngle sound record thereon adjacent one row of sprocket holes. The film is driven jointly by the sprocket 7 and the drum 8, these two members being connected by mechanism, now 5 to be described, to the common motor-driven shaft 9. Worm 11 on shaft 9 meshes with the worm wheel 12 which through gears 13, 14 and 15 drive shaft 16 of sprocket 7 Worm gear 12 also drives shaft 18 to which is secured at one end the flywheel 19 and at the other end the drum 8 but at a speed which is variable within certain limits and automatically controlled so that regardless of the amount of shrinkage the film may have undergone the drum will move the film at exactly thesame speed as it is moved by the sprocket. The compensator for effecting this variable speed drive is driven from the worm gear 12 through an elastic or cushioning connection comprising the ring 20 of leather or other suitable material having a series of holes into which extend pins 21. Alternate pins are fixed in the worm gear 12 and the internal gear member 22 which is journalled on a sleeve of the worm gear. Loosel mounted on shaft 18 is the brake wheel'24 liavin the hub 25 which is eccentric with the sha 18. Journalled in this eccentric hub is the gear member 26 having two sets of teeth forming two gears of which the pitch diameter of the one is slightly smaller than that of the other.

The internal gear member 22 meshes with the larger gear and internal gear member 27 meshes with the smaller gear. This gear member 27 has a sleeve portion which is keyed to shaft 18 and which forms a bearing for the worm gear. Brake 28 is arranged to be applied with variable pressure to the brake wheel 24. The parts above described are so constructed that when the brake is not applied to the brake wheel and the gear mechanism associated therewith rotates freely the drum 8 is driven at such a speed that it moves the film appreciably faster than does the sprocket 7 regardless of how little shrinkage that the film may have undergone. If the brake is applied hard enough to hold the brake wheel immovable then the speed of the drum is decreased to such an extent that it moves the film appreciably slower than does the sprocket even though the film has undergone the maximum amount of shrinkage.

Between the sprocket and the drum the film passes through the two loops 30 and 31 enlevers 34 and 35. The opgosige ends of these to the brake-apphed position by the spring 43. As so arranged spring 43 op oses sprin 36. In normal 0 ration and af ter the first few feet offilm as passed through the apparatus the brake 28 is but lightly apphed to e the brake wheel and there is no perce tible drum and passes over the member) guide portions is movement of the lever 34. Although 0 reaction of the arm 39 on lever 34 is shght I compensate for this efi'ect on the film tensions in loops and 31 by slightly changing the lengths of the corresponding lever arms of levers 34 and 35, for example, by shghtly lengthening the lower or short arm of ever 35. Thus the film tension in the two loops 30 and 31 can be maintained durin the operation of the machine verv closel i not exactly the same. This condition I ave found to be essential if no slippage is to occur between the film and the drum. a

For pressing the film agalnst the sprocket 7 I have shown the two ressurerolls 46 and 47 and for pressing the against the face of the drum I have shown the two pressure rolls 48 and 49. Roll 48 also is a guide roll having flanges which position the film axially on the drum. The film it will be seen makes contact with the drum at two separated portions of its circumference, one of WhlCh is of greater extent than the other. Between these two contact portions the film leaves the p forming a skid and containing the phot -'e ectric cell 51. Member 50 is shown formed in two parts, a metallic base or socket member 53 and a metallic cell housing 54. The socket member 53 is shown attached to a wall of the metal casing 1 and contains the socket contacts 55 with which detachable connection is made to the contact lugs on the base of the cell 51. Preferably the cell is mounted in the housing 54, suitable acking such as, for example, felt being rovided between the cell and the housing walls.

The housingwith the cell is detachably secured in the socket 53 by any suitable means such, for example, as the clamp 56. I construct the hou 54 preferably of steel thereby better to resist the wear of the and polish those rtions of'the cyhndrlcal surface thereof w ch engage and guide the marginal portions of the film. Between the th depressed portion 58. An optical system sli own in part at proecting through the: casing wall focuses a am of light down to a narrow band on the film as it passes over the skid. At a int d 1- rectly beneath this focused light ban the skid or housing 54 is provided with the hght aperture 61 through which the light under the control of the sound record on the film may pass intothe photo-electric cell, see Fi s. 3 and 5. By depressing that rtion of the ousing beneath the art of t e film bearing the sound record an in the case of a sound-picture film the part of the film bearin both the sound and the picture record the film is subjected to less wear and the records are less liable to beg come scratched. Dust and dirt carried along by the film also is less liable to be carried into the light aperture. To further insure against the collection of dust. and dirt in' the light aperture I make the additional depression 62 in the housing connecting with the aperture. Thus any particles of foreign matter such as dust, dirt wax, etc., carried by the film toward the aperture will be sweptawa before finding lodginent in the aperture. f desired the cell ousing may be provided with more than one light aperture as shown for example at Fig. 4 whereby in the event that the ide portions of the housin become worn ad] acent one aperture the housing may be turned relative to the socket and the cell to bring another aperture into use.

The drum 8 having the flywheel mounted directly on its shaft drives the film over the reater an le after it leaves the skid than beore reachln'g it, that free stretch of film be-' tween the skid and the point of contact of drum and roller 48 will always keep taut.

In the'present illustration I have shown the leads 64 from the socket contacts 55 carried through a metallic conduit 65 to a metallic transformer housing 66. Within this housing the leads connect with a suitable transformer, not shown, from which connections are made to ampli g apparatus of well known character an thence to a loud speaker or other translating device as desired.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus'for supportingv and moving at a uni orm speed a "sound record film comprising a drum having an inertia member associated therewith, means for rotating the drum, means for pressing the film against the face of the drum at two spaced peripheral portions thereof, a curved skid arranged to support a loop in the film between the points of contact of the film and the drum, a photoelectric cell and means for directing a light beam into the cell. and through the film adjacent its point of support by the skid.

2. Apparatus'for-supporting and driving at a mu curved skid having a light aperture therein arranged to engage and support a loop in the film between said spaced portions, a photoelectric cell and means for projecting light through the aperture in the skid and the film thereon into the cell. I

3. Apparatus of the character described comprising aphoto-electric cell, a housing therefor having a light aperture and a smooth face over which a sound record film is adapted to be drawn, means for projecting a narrow light beam through the film and the aperture into the cell and means for drawing the film over said housing with a uniform speed independent of sprocket tooth vibrations comprising a drum, a flywheel directly connected therewith and means for causing the film to engage the drum both before and after it passes over said housing.

7 socket member secured thereto, a film supber enclosing the rting housing member detachably connected to said socket member, a photo-electric cell mounted in said member and having contacts adapted to engage the contacts therein, said member having spacedportions forming continuous guide surfaces adapted to be engaged by the marginal portions of a sound record film and having a light apergure therein arranged between said guide suraces.

6. Apparatus of the character described comprism a photo-electric cell, a fixed memcell and forming a film support, said member having continuous curved guide portions adapted to be engaged by the marginal portions of a sound record film and having an intermediate depressed 'POI'tlOD, said member having a light aperture'therein arran ed between t e gulde portions thereof.

' 7. pparatus of the character described A comprising a photo-electric cell, a cylindrical housing enclosing the cell and forming a film support, said housing having portions forming continuous guide surfaces adapted to be engaged by the marginal portions of a sound record film and having an intermediate depressed portion, said housing having a light aperture therein in thedepressed portion and ortionconnecthaving a further depressed ing with the aperture at t e I trailing side thereof.

8. Apparatus of the-characterdescribei 55 comprising an enclosing casing, a shaft extending through a wall thereof, a drum in said casing secured to the end of said shaft, said drum being adapted to engage a film at two separate portions of its periphery, a housing detachably secured to said wall adjacent said drum and adapted to form a support for a loop of said film between the contact portions of the film and the drum, and a photoelectric cell mounted in said detachable houslng.

In witness whereof, I have hereunto set. my hand this 28th da of March, 1929.

C ARLES L. HEISLER. 

